Inferring the Neutron Star Maximum Mass and Lower Mass Gap in Neutron Star–Black Hole Systems with Spin
Inferring the Neutron Star Maximum Mass and Lower Mass Gap in Neutron Star–Black Hole Systems with Spin
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DOI：
10.3847/1538-4357/ac7f99
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发表时间：
2022-01
期刊：
影响因子：
--
通讯作者：
C. Ye;M. Fishbach
中科院分区：
文献类型：
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作者：
C. Ye;M. Fishbach
引力波(GW)探测合并中子星-黑洞(NSBH)系统探测天体物理中子星(NS)和黑洞(BH)的质量分布，特别是在NS和BH质量之间的过渡区。特别令人感兴趣的是最大NS质量、最小BH质量以及它们之间的潜在质量差距。虽然以前的GW布居分析假设所有NSS服从相同的最大质量，但如果存在快速旋转的NSS，它们可以扩展到比不旋转的NSS更大的最大质量。事实上，几位作者已经提出，GW190814事件中的∼2.6M⊙天体--要么是迄今为止观测到的质量最大的NS，要么是质量最小的BH--是一个快速旋转的NS。因此，我们联合推导出NSBH质量分布和NS自旋分布，将NS最大质量模拟为自旋的函数。使用包括GW190814在内的四个LIGO-Virgo NSBH事件，如果我们假设NS自旋分布均匀直到最大自旋(解体)，我们推导出最大非自旋NS质量为2.7−0.4+0.5M⊙(90%可信度)，而仅假设非自旋NSS，NS最大质量必须为>；2.53M⊙(90%可信度)。数据支持质量隙的存在，其最小质量为5.4MH1.0+0.7M−。随着未来的观测，在简化的假设下，150NSBH事件可能会将最大非自旋NS质量限制在±0.02M⊙，我们甚至可能完全根据GW数据测量NS自旋与最大质量之间的关系。如果存在快速旋转的NSS，则必须同时对它们的自转和质量进行建模，以避免偏向NS的最大质量。
Gravitational-wave (GW) detections of merging neutron star–black hole (NSBH) systems probe astrophysical neutron star (NS) and black hole (BH) mass distributions, especially at the transition between NS and BH masses. Of particular interest are the maximum NS mass, minimum BH mass, and potential mass gap between them. While previous GW population analyses assumed all NSs obey the same maximum mass, if rapidly spinning NSs exist, they can extend to larger maximum masses than nonspinning NSs. In fact, several authors have proposed that the ∼2.6 M ⊙ object in the event GW190814—either the most massive NS or least massive BH observed to date—is a rapidly spinning NS. We therefore infer the NSBH mass distribution jointly with the NS spin distribution, modeling the NS maximum mass as a function of spin. Using four LIGO–Virgo NSBH events including GW190814, if we assume that the NS spin distribution is uniformly distributed up to the maximum (breakup) spin, we infer the maximum nonspinning NS mass is 2.7−0.4+0.5M⊙ (90% credibility), while assuming only nonspinning NSs, the NS maximum mass must be >2.53 M ⊙ (90% credibility). The data support the mass gap’s existence, with a minimum BH mass at 5.4−1.0+0.7M⊙ . With future observations, under simplified assumptions, 150 NSBH events may constrain the maximum nonspinning NS mass to ±0.02 M ⊙, and we may even measure the relation between the NS spin and maximum mass entirely from GW data. If rapidly rotating NSs exist, their spins and masses must be modeled simultaneously to avoid biasing the NS maximum mass.